content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
   * Other names may be trademarks of their respective owners.]
   *
   * -------------------
   * GrayPaintScale.java
   * -------------------
   * (C) Copyright 2006-2013, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 05-Jul-2006 : Version 1 (DG);
   * 31-Jan-2007 : Renamed min and max to lowerBound and upperBound (DG);
   * 26-Sep-2007 : Fixed bug 1767315, problem in getPaint() method (DG);
   * 29-Jan-2009 : Added alpha transparency field and hashCode() method (DG);
   * 17-Jun-2012 : Removed JCommon dependencies (DG);
   *
   */
  
  package org.jfree.chart.renderer;
  
  import java.awt.Color;
  import java.awt.Paint;
  import java.io.Serializable;
  
  import org.jfree.chart.HashUtilities;
  import org.jfree.chart.util.PublicCloneable;
  
  /**
   * A paint scale that returns shades of gray.
   *
   * @since 1.0.4
   */
  public class GrayPaintScale implements PaintScale, PublicCloneable,
          Serializable {
  
      /** The lower bound. */
      private double lowerBound;
  
      /** The upper bound. */
      private double upperBound;
  
      /**
       * The alpha transparency (0-255).
       *
       * @since 1.0.13
       */
      private int alpha;
  
      /** Cache of shades. */
      private Color[] shades = new Color[256];
  
      /**
       * Creates a new <code>GrayPaintScale</code> instance with default values.
       */
      public GrayPaintScale() {
          this(0.0, 1.0);
      }
  
      /**
       * Creates a new paint scale for values in the specified range.
       *
       * @param lowerBound  the lower bound.
       * @param upperBound  the upper bound.
       *
       * @throws IllegalArgumentException if <code>lowerBound</code> is not
       *       less than <code>upperBound</code>.
       */
      public GrayPaintScale(double lowerBound, double upperBound) {
          this(lowerBound, upperBound, 255);
      }
  
      /**
       * Creates a new paint scale for values in the specified range.
       *
       * @param lowerBound  the lower bound.
       * @param upperBound  the upper bound.
       * @param alpha  the alpha transparency (0-255).
       *
       * @throws IllegalArgumentException if <code>lowerBound</code> is not
       *       less than <code>upperBound</code>, or <code>alpha</code> is not in
       *       the range 0 to 255.
       *
       * @since 1.0.13
       */
      public GrayPaintScale(double lowerBound, double upperBound, int alpha) {
          if (lowerBound >= upperBound) {
              throw new IllegalArgumentException(
                      "Requires lowerBound < upperBound.");
          }
          if (alpha < 0 || alpha > 255) {
              throw new IllegalArgumentException(
                      "Requires alpha in the range 0 to 255.");
  
          }
          this.lowerBound = lowerBound;
          this.upperBound = upperBound;
          this.alpha = alpha;
      }
  
      /**
       * Returns the lower bound.
       *
       * @return The lower bound.
       *
       * @see #getUpperBound()
       */
      @Override
      public double getLowerBound() {
          return this.lowerBound;
      }
  
      /**
       * Returns the upper bound.
       *
       * @return The upper bound.
       *
       * @see #getLowerBound()
       */
      @Override
      public double getUpperBound() {
          return this.upperBound;
      }
  
      /**
       * Returns the alpha transparency that was specified in the constructor.
       *
       * @return The alpha transparency (in the range 0 to 255).
       *
       * @since 1.0.13
       */
      public int getAlpha() {
          return this.alpha;
      }
  
      /**
       * Returns a paint for the specified value.
       *
       * @param value  the value (must be within the range specified by the
       *         lower and upper bounds for the scale).
       *
       * @return A paint for the specified value.
       */
      @Override
      public Paint getPaint(double value) {
          double v = Math.max(value, this.lowerBound);
          v = Math.min(v, this.upperBound);
          int g = (int) ((v - this.lowerBound) / (this.upperBound
                  - this.lowerBound) * 255.0);
          if (this.shades[g] == null) {
              this.shades[g] = new Color(g, g, g, this.alpha);
          }
          return this.shades[g];
      }
  
      /**
       * Tests this <code>GrayPaintScale</code> instance for equality with an
       * arbitrary object.  This method returns <code>true</code> if and only
       * if:
       * <ul>
       * <li><code>obj</code> is not <code>null</code>;</li>
       * <li><code>obj</code> is an instance of <code>GrayPaintScale</code>;</li>
       * </ul>
       *
       * @param obj  the object (<code>null</code> permitted).
       *
       * @return A boolean.
       */
      @Override
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
          }
          if (!(obj instanceof GrayPaintScale)) {
              return false;
          }
          GrayPaintScale that = (GrayPaintScale) obj;
          if (this.lowerBound != that.lowerBound) {
              return false;
          }
          if (this.upperBound != that.upperBound) {
              return false;
          }
          if (this.alpha != that.alpha) {
              return false;
          }
          return true;
      }
  
      /**
       * Returns a hash code for this instance.
       *
       * @return A hash code.
       */
      @Override
      public int hashCode() {
          int hash = 7;
          hash = HashUtilities.hashCode(hash, this.lowerBound);
          hash = HashUtilities.hashCode(hash, this.upperBound);
          hash = 43 * hash + this.alpha;
          return hash;
      }
  
      /**
       * Returns a clone of this <code>GrayPaintScale</code> instance.
       *
       * @return A clone.
       *
       * @throws CloneNotSupportedException if there is a problem cloning this
       *     instance.
       */
      @Override
      public Object clone() throws CloneNotSupportedException {
          return super.clone();
      }
  
  }
  